OK. This is simple. Just buy from Akara a Scroll of Town Portal and go to see Andariel. Make sure you have potions & antidotes because she has a poison attack. Fight her and hurt her about to the half of her health bar. Then run to the room outside Andariel's lair and use the scroll of town portal or tome of town portal and go to rogue encampment. Heal yourself and do all the arrangements that you have to and go to visit Andariel, again. Now she has half her health, IT'S MAGIC!!!! Now kill her and pick up her stuff and WOW you are in ACT II.